马尾松造林密度与林分生长效应试验

采用1.4 m×1.4 m、1.1 m×1.2 m、1 m×1 m、0.5 m×1.0 m等4种株行距进行马尾松短周期工业原料林造林试验,通过7 a的定位观测表明,1.1 m×1.2 m的造林株行距是定向培育马尾松短周期工业原料林的较适合密度。     

不同造林密度对培育马尾松造纸工艺林生长的影响

采用1.4m×1.4m、1.1m×1.2m、1m×1m、0.5m×0.5m等4种株行距进行马尾松造纸工艺林造林,通过7年的定位观测表明,1.1m×1.2m的造林株行距是定向培育马尾松造纸工艺林的较适合密度。     

西南桦的栽培技术

在对西南桦的生物学特性、生长、用途以及分布区较详细论述的基础上 ,主要对西南桦的栽培技术进行了研究。结果表明 ,发展西南桦人工林的关键在于选用适生种源 ,适时采种 ,正确处理和保存种子 ,种子必须低温 (10℃以下 )保存。造林最好用营养苗 ,7～ 8月播种 ,10月中～ 11月中将芽苗移入营养袋内继续培育 ,3～ 4月出圃造林。育苗基质要疏松 ,排水性能要好 ,苗期要加强水肥管理 ,苗高 2 0～ 30 cm时出圃造林。在上年的 11～ 12月整地 ,采用带状或穴状整地方式 ,穴要大(5 0 cm× 5 0 cm× 4 0 cm)。造林要适时 ,一般 3～ 4月 ,在干湿季明显的地区 ,7～ 8月雨季定植 ,造林密度 2 m× 3m或 3m× 3m。造林前施基肥 ,造林后要加强抚育管理和追肥 ,连续进行 3a。对造林密度为 2 m× 3m的林分 ,植后 6～ 8a要进行第 1次间伐。     

华北干旱石质阳坡油松营养杯苗造林技术

<正>随着生态建设的推进,干旱石质阳坡造林成为灭荒攻艰的主战场。由于立地条件差、气候干旱等因素影响,导致造林成活率低,制约了造林绿化步伐。为此,笔者经过几年的探索实践,采用油松营养杯苗造林技术,成活率、保有率达90%以上,既节约了造林资金、提高了投资效益,又加快了荒山绿化进程。1造林地准备在干旱石质阳坡造林,于造林前一年雨季采用环山竹节壕整地,规格为1.3m×0.5m×0.5m,竹节壕间距1m,行距     

江洲滩地杨树造林关键技术研究

通过总结联合国粮农组织援建的“中国东部暖温带杨树丰产林”经验,认为江州滩地杨树造林关键技术是造林时间以11月至翌年2月为宜;缩小植穴口径,深栽80cm后培土至地上50cm,造林选用1、2年生苗,密度可选3m×3m,3m×4m,4m×10m或者4m×4m,造林前需清除芦苇。     

卵叶海桑的育苗和造林技术

卵叶海桑 (Sonneratiaovata)可适应土壤结实、贫瘠 ,水分较低的残次林地造林。一年四季均可播种。种子发芽期间 ,水分盐度控制 5‰以内 ,幼苗控制 8‰以内 ,随着幼苗的长大逐步提高水分盐度。造林季节 3～ 8月 ,在裸滩造林 ,造林密度 3m× 4m或 4m× 4m ;残次林改造 ,造林密度 4m× 5m ,4m× 6m。     

甜大节竹丰产栽培试验研究

设计甜大节竹不同时间、不同材料育苗试验和不同造林密度(间种农作物)对比试验研究,经过近8年试验观测,结果是用截杆留鞭育苗,原产地成活率83.3%,引种育苗试验成活率64.2%;采用3m×3m造林密度,栽竹2a,出笋率90.4%,栽竹5a,鲜笋产量365.6kg/667m2。     

水杉造林密度试验

为水杉造林选择造林密度,提供参考依据。通过研究水杉不同造林密度对林分活立木总蓄积和经济效益的影响,本次试验设置了A水平:2.0m×2.0m,B水平:2.0m×2.5 m,C水平:2.0m×3.0m,3个规格,隔离带造林密度为3.0m×3.0m。通过这3个不同的造林密度水平试验,结果表明:造林密度的大小随着林龄增大对立木材积的影响变小,对经济效益的影响则变大。     

鹅掌揪不同造林密度试验初报

三种不同造林密度试验的15年生鹅掌揪调查结果表明,不同的造林密度对鹅掌揪的树高、胸径及单株材积有显著性的影响,而对蓄积量的影响不显著。其中造林密度为2．5m×2．5m的树高、胸径及单株材积量最大,经济效益也最高;而造林密度为1．5m×1．5m的树高、胸径及单株材积量最小,经济效益也最低。在目前的造林生产中,以2．5m×2．5m的造林密度为最佳。     

侧柏容器苗的培育及其造林技术试验研究小结

容器苗造林是解决干旱、瘠薄、石质山地阳坡造林主要方法之一。朝阳1980—1983年连续干旱,降雨量为正常年降雨量的60％左右。地下水位平均下降7m,用裸根苗造林成活率低。为提高阳坡造林成活率,从1982—1984年对侧柏(Thuja orientelie L.)容器苗的培育及其造林技术进行了试验研究。试验分育苗、造林两个阶段,每个阶段搞三个重复进行对比。一、试验设置与方法 (一)容器苗的培育 1.圃地的选择及作床。容器育苗采用室     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.